static void server_recv_cb(EV_P_ ev_io *w, int revents)
{
struct server_ctx *server_recv_ctx = (struct server_ctx *)w;
struct server *server = server_recv_ctx->server;
struct remote *remote = NULL;
int len = server->buf_len;
char **buf = &server->buf;
ev_timer_again(EV_A_ & server->recv_ctx->watcher);
if (server->stage != 0) {
remote = server->remote;
buf = &remote->buf;
len = 0;
}
ssize_t r = recv(server->fd, *buf + len, BUF_SIZE - len, 0);
if (r == 0) {
// connection closed
if (verbose) {
LOGI("server_recv close the connection");
}
close_and_free_remote(EV_A_ remote);
close_and_free_server(EV_A_ server);
return;
} else if (r == -1) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
// no data
// continue to wait for recv
return;
} else {
ERROR("server recv");
close_and_free_remote(EV_A_ remote);
close_and_free_server(EV_A_ server);
return;
}
}
tx += r;
// handle incomplete header
if (server->stage == 0) {
r += server->buf_len;
if (r <= enc_get_iv_len()) {
// wait for more
if (verbose) {
#ifdef __MINGW32__
LOGI("imcomplete header: %u", r);
#else
LOGI("imcomplete header: %zu", r);
#endif
}
server->buf_len = r;
return;
} else {
server->buf_len = 0;
}
}
*buf = ss_decrypt(BUF_SIZE, *buf, &r, server->d_ctx);
if (*buf == NULL) {
LOGE("invalid password or cipher");
report_addr(server->fd);
close_and_free_remote(EV_A_ remote);
close_and_free_server(EV_A_ server);
return;
}
// handshake and transmit data
if (server->stage == 5) {
if (server->auth
&& !ss_check_crc(remote->buf, &r, server->crc_buf, &server->crc_idx)) {
LOGE("crc error");
report_addr(server->fd);
close_and_free_server(EV_A_ server);
close_and_free_remote(EV_A_ remote);
return;
}
int s = send(remote->fd, remote->buf, r, 0);
if (s == -1) {
if (errno == EAGAIN || errno == EWOULDBLOCK) {
// no data, wait for send
remote->buf_len = r;
remote->buf_idx = 0;
ev_io_stop(EV_A_ & server_recv_ctx->io);
ev_io_start(EV_A_ & remote->send_ctx->io);
} else {
ERROR("server_recv_send");
close_and_free_remote(EV_A_ remote);
close_and_free_server(EV_A_ server);
}
} else if (s < r) {
remote->buf_len = r - s;
remote->buf_idx = s;
ev_io_stop(EV_A_ & server_recv_ctx->io);
ev_io_start(EV_A_ & remote->send_ctx->io);
}
return;
} else if (server->stage == 0) {
/*
* Shadowsocks TCP Relay Protocol:
*
* +------+----------+----------+-----------------+
* | ATYP | DST.ADDR | DST.PORT | AUTH (Optional) |
* +------+----------+----------+-----------------+
* | 1 | Variable | 2 | 16 |
* +------+----------+----------+-----------------+
*
* If ATYP & ONETIMEAUTH_FLAG(0x10) == 1, AUTH and CRC are enabled.
*/
/*
* Shadowsocks TCP Request Payload CRC (Optional, no CRC for response's payload):
*
* +------+------+------+------+------+
* | DATA | CRC8 | DATA | CRC8 | ...
* +------+------+------+------+------+
* | 128 | 1 | 128 | 1 | ...
* +------+------+------+------+------+
*/
int offset = 0;
int need_query = 0;
char atyp = server->buf[offset++];
char host[256] = { 0 };
uint16_t port = 0;
struct addrinfo info;
struct sockaddr_storage storage;
memset(&info, 0, sizeof(struct addrinfo));
memset(&storage, 0, sizeof(struct sockaddr_storage));
// get remote addr and port
if ((atyp & ADDRTYPE_MASK) == 1) {
// IP V4
struct sockaddr_in *addr = (struct sockaddr_in *)&storage;
size_t in_addr_len = sizeof(struct in_addr);
addr->sin_family = AF_INET;
if (r > in_addr_len) {
addr->sin_addr = *(struct in_addr *)(server->buf + offset);
dns_ntop(AF_INET, (const void *)(server->buf + offset),
host, INET_ADDRSTRLEN);
offset += in_addr_len;
} else {
LOGE("invalid header with addr type %d", atyp);
report_addr(server->fd);
close_and_free_server(EV_A_ server);
return;
}
addr->sin_port = *(uint16_t *)(server->buf + offset);
info.ai_family = AF_INET;
info.ai_socktype = SOCK_STREAM;
info.ai_protocol = IPPROTO_TCP;
info.ai_addrlen = sizeof(struct sockaddr_in);
info.ai_addr = (struct sockaddr *)addr;
} else if ((atyp & ADDRTYPE_MASK) == 3) {
// Domain name
uint8_t name_len = *(uint8_t *)(server->buf + offset);
if (name_len < r) {
memcpy(host, server->buf + offset + 1, name_len);
offset += name_len + 1;
} else {
LOGE("invalid name length: %d", name_len);
report_addr(server->fd);
close_and_free_server(EV_A_ server);
return;
}
struct cork_ip ip;
if (cork_ip_init(&ip, host) != -1) {
info.ai_socktype = SOCK_STREAM;
info.ai_protocol = IPPROTO_TCP;
if (ip.version == 4) {
struct sockaddr_in *addr = (struct sockaddr_in *)&storage;
dns_pton(AF_INET, host, &(addr->sin_addr));
addr->sin_port = *(uint16_t *)(server->buf + offset);
addr->sin_family = AF_INET;
info.ai_family = AF_INET;
info.ai_addrlen = sizeof(struct sockaddr_in);
info.ai_addr = (struct sockaddr *)addr;
} else if (ip.version == 6) {
struct sockaddr_in6 *addr = (struct sockaddr_in6 *)&storage;
dns_pton(AF_INET6, host, &(addr->sin6_addr));
addr->sin6_port = *(uint16_t *)(server->buf + offset);
addr->sin6_family = AF_INET6;
info.ai_family = AF_INET6;
info.ai_addrlen = sizeof(struct sockaddr_in6);
info.ai_addr = (struct sockaddr *)addr;
}
} else {
need_query = 1;
}
} else if ((atyp & ADDRTYPE_MASK) == 4) {
// IP V6
struct sockaddr_in6 *addr = (struct sockaddr_in6 *)&storage;
size_t in6_addr_len = sizeof(struct in6_addr);
addr->sin6_family = AF_INET6;
if (r > in6_addr_len) {
addr->sin6_addr = *(struct in6_addr *)(server->buf + offset);
dns_ntop(AF_INET6, (const void *)(server->buf + offset),
host, INET6_ADDRSTRLEN);
offset += in6_addr_len;
} else {
LOGE("invalid header with addr type %d", atyp);
report_addr(server->fd);
close_and_free_server(EV_A_ server);
return;
}
addr->sin6_port = *(uint16_t *)(server->buf + offset);
info.ai_family = AF_INET6;
info.ai_socktype = SOCK_STREAM;
info.ai_protocol = IPPROTO_TCP;
info.ai_addrlen = sizeof(struct sockaddr_in6);
info.ai_addr = (struct sockaddr *)addr;
}
if (offset == 1) {
LOGE("invalid header with addr type %d", atyp);
report_addr(server->fd);
close_and_free_server(EV_A_ server);
return;
}
if (acl && !need_query && acl_contains_ip(host)) {
if (verbose) {
LOGI("Access denied to %s", host);
}
close_and_free_server(EV_A_ server);
return;
}
port = (*(uint16_t *)(server->buf + offset));
offset += 2;
if (auth || (atyp & ONETIMEAUTH_FLAG)) {
if (ss_onetimeauth_verify(server->buf + offset, server->buf, offset)) {
LOGE("authentication error %d", atyp);
report_addr(server->fd);
close_and_free_server(EV_A_ server);
return;
};
offset += ONETIMEAUTH_BYTES;
server->auth = 1;
}
if (verbose) {
LOGI("connect to: %s:%d", host, ntohs(port));
}
// XXX: should handle buffer carefully
if (r > offset) {
server->buf_len = r - offset;
server->buf_idx = offset;
}
if (server->auth
&& !ss_check_crc(server->buf + server->buf_idx, &server->buf_len, server->crc_buf, &server->crc_idx)) {
LOGE("crc error");
report_addr(server->fd);
close_and_free_server(EV_A_ server);
return;
}
if (!need_query) {
struct remote *remote = connect_to_remote(&info, server);
if (remote == NULL) {
LOGE("connect error");
close_and_free_server(EV_A_ server);
return;
} else {
server->remote = remote;
remote->server = server;
// XXX: should handle buffer carefully
if (server->buf_len > 0) {
memcpy(remote->buf, server->buf + server->buf_idx,
server->buf_len);
remote->buf_len = server->buf_len;
remote->buf_idx = 0;
server->buf_len = 0;
server->buf_idx = 0;
}
server->stage = 4;
// listen to remote connected event
ev_io_stop(EV_A_ & server_recv_ctx->io);
ev_io_start(EV_A_ & remote->send_ctx->io);
}
} else {
server->stage = 4;
server->query = resolv_query(host, server_resolve_cb, NULL, server,
port);
ev_io_stop(EV_A_ & server_recv_ctx->io);
}
return;
}
// should not reach here
FATAL("server context error");
}
int ss_decrypt_all(buffer_t *cipher, int method, int auth, size_t capacity)
{
if (method > TABLE) {
size_t iv_len = enc_iv_len;
int ret = 1;
if (cipher->len <= iv_len) {
return -1;
}
cipher_ctx_t evp;
cipher_context_init(&evp, method, 0);
static buffer_t tmp = { 0, 0, 0, NULL };
brealloc(&tmp, cipher->len, capacity);
buffer_t *plain = &tmp;
plain->len = cipher->len - iv_len;
uint8_t iv[MAX_IV_LENGTH];
memcpy(iv, cipher->array, iv_len);
cipher_context_set_iv(&evp, iv, iv_len, 0);
if (method >= SALSA20) {
crypto_stream_xor_ic((uint8_t *)plain->array,
(const uint8_t *)(cipher->array + iv_len),
(uint64_t)(cipher->len - iv_len),
(const uint8_t *)iv, 0, enc_key, method);
} else {
ret = cipher_context_update(&evp, (uint8_t *)plain->array, &plain->len,
(const uint8_t *)(cipher->array + iv_len),
cipher->len - iv_len);
}
if (auth || (plain->array[0] & ONETIMEAUTH_FLAG)) {
if (plain->len > ONETIMEAUTH_BYTES) {
ret = !ss_onetimeauth_verify(plain, iv);
if (ret) {
plain->len -= ONETIMEAUTH_BYTES;
}
} else {
ret = 0;
}
}
if (!ret) {
bfree(cipher);
cipher_context_release(&evp);
return -1;
}
#ifdef DEBUG
dump("PLAIN", plain->array, plain->len);
dump("CIPHER", cipher->array + iv_len, cipher->len - iv_len);
#endif
cipher_context_release(&evp);
brealloc(cipher, plain->len, capacity);
memcpy(cipher->array, plain->array, plain->len);
cipher->len = plain->len;
return 0;
} else {
char *begin = cipher->array;
char *ptr = cipher->array;
while (ptr < begin + cipher->len) {
*ptr = (char)dec_table[(uint8_t)*ptr];
ptr++;
}
return 0;
}
}
char * ss_decrypt_all(int buf_size, char *ciphertext, ssize_t *len, int method, int auth)
{
if (method > TABLE) {
size_t iv_len = enc_iv_len;
size_t c_len = *len, p_len = *len - iv_len;
int ret = 1;
if (*len <= iv_len) {
return NULL;
}
cipher_ctx_t evp;
cipher_context_init(&evp, method, 0);
static int tmp_len = 0;
static char *tmp_buf = NULL;
int buf_len = max(p_len, buf_size);
if (tmp_len < buf_len) {
tmp_len = buf_len;
tmp_buf = realloc(tmp_buf, buf_len);
}
char *plaintext = tmp_buf;
uint8_t iv[MAX_IV_LENGTH];
memcpy(iv, ciphertext, iv_len);
cipher_context_set_iv(&evp, iv, iv_len, 0);
if (method >= SALSA20) {
crypto_stream_xor_ic((uint8_t *)plaintext,
(const uint8_t *)(ciphertext + iv_len),
(uint64_t)(c_len - iv_len),
(const uint8_t *)iv, 0, enc_key, method);
} else {
ret = cipher_context_update(&evp, (uint8_t *)plaintext, &p_len,
(const uint8_t *)(ciphertext + iv_len),
c_len - iv_len);
}
if (auth || (plaintext[0] & ONETIMEAUTH_FLAG)) {
if (p_len > ONETIMEAUTH_BYTES) {
char hash[ONETIMEAUTH_BYTES];
memcpy(hash, plaintext + p_len - ONETIMEAUTH_BYTES, ONETIMEAUTH_BYTES);
ret = !ss_onetimeauth_verify(hash, plaintext, p_len - ONETIMEAUTH_BYTES, iv);
if (ret) {
p_len -= ONETIMEAUTH_BYTES;
}
} else {
ret = 0;
}
}
if (!ret) {
free(ciphertext);
cipher_context_release(&evp);
return NULL;
}
#ifdef DEBUG
dump("PLAIN", plaintext, p_len);
dump("CIPHER", ciphertext + iv_len, c_len - iv_len);
#endif
cipher_context_release(&evp);
if (buf_size < p_len) {
ciphertext = realloc(ciphertext, p_len);
}
*len = p_len;
memcpy(ciphertext, plaintext, *len);
return ciphertext;
} else {
char *begin = ciphertext;
while (ciphertext < begin + *len) {
*ciphertext = (char)dec_table[(uint8_t)*ciphertext];
ciphertext++;
}
return begin;
}
}
